Interface of a tool

ABSTRACT

An interface of a tool is proposed with a first part serving as a seat having a female taper, which part has a first conduit section located concentrically to its center axis, a second part having a hollow shaft taper introduceable into the recess, which part has a second conduit section located concentrically to its center axis, where the center axes of the first and second parts align and having a collet chuck having two chuck jaws which comprises an actuating device coacting with the chuck jaws which can be activated by means of an actuating element. The characteristic feature of the interface is that the actuating device ( 43 ) has a caging element ( 47 ) which can be shifted to two operating positions and which has a central passage ( 71 ) which is located such that the center axes of the first and second parts ( 3, 5 ) pass through said passage.

The invention relates to an interface of a tool in accordance with thepreamble of claim 1.

Interfaces of the type addressed here are well known. The term interfacedescribes the connecting point between a machine spindle and a tool, amachine spindle and an adapter, an adapter and a tool, and similar; ingeneral, the connecting point between two elements of a tool system. Inthe case of the tools being addressed here, they are those which removecuttings from a work piece by means of a geometrically defined cutter,with the tool usually being set in rotational motion. A first part ofthe interface acts as the seat and has a female taper into which ahollow shank taper of a second part of the interface can be inserted.The hollow shank taper of the second part is pulled into the femaletaper of the first part by means of a clamping fixture, as a result ofwhich typically circular flat surfaces on the first and second part arein tight contact with each other. In addition, the hollow shaft taper ispreferably expanded slightly so that it abuts the inner surface of thefemale taper in the seat. The result is, first of all, exact alignmentof the two parts of the interface and, secondly, a very high degree ofrigidity. The clamping fixture has a collet chuck with two jaws whichare moveable in the radial direction by means of an actuating device,that is to say, perpendicular to the axis of rotation of the tool. Thecollect chuck is anchored to the first part such that any axialdisplacement is prevented. The jaws coact with clamping shoulders on thehollow shaft taper such that the latter is drawn into the female taper.The displacement of the jaws is effected by means of an actuating devicewhich can be activated through an actuator. Known interfaces haveclamping screws which act as an actuating device and have two sectionswith opposite-hand threads. They coact with the chuck jaws and urge saidjaws radially outward and inward, depending on the direction of rotationof the clamping screw. For example, an Allen wrench serving as theactuating device can be inserted into a matching recess in a clampingscrew in order to rotate said screw to the right or to the left.

Minimum quantity lubrication is preferably used when machining workpieces, in which an air/oil mixture is used as the coolant and lubricantin place of an emulsion. The oil is present in extremely finelydistributed droplets which float in the air and form a type of mistwhich wets the cutter(s) of a tool while a work piece is being machined,as well as any guideways if the need arises. In supplying the air/oilmixture, it is of crucial importance that as few changes of direction aspossible, meaning deviations from a straight run, are present in thesupply conduits because separation and pooling occur in the area of thebends. In the case of the known interface being discussed here, that is,using a clamping screw as the actuating device, a straight run for thesupply passages for minimum quantity lubrication is not possible becausethe clamping screw runs perpendicularly through the body of the collectchuck.

The object of the invention is, therefore, to create an interface whichis characterized by an improved coolant supply.

To achieve this object, an interface is proposed which has the featuresnamed in claim 1. The characteristic feature of the interface is thatthe actuating device which coacts with the jaws of the collect chuck isconfigured as a caging element which is moveable to two operatingpositions, having a central passage for the coolant/lubricant. Thepassage is located such that its center axis coincides with the centeraxes of the first and second part. Because the passage aligns withconduit sections in the first and second parts, changes of direction areavoided at which separation and pooling can occur. The interface withthe features named here permits minimum quantity lubrication without anyoccurrence of the disadvantages named.

In a preferred embodiment of the interface, the actuating device isaccessible through a first radial recess in the hollow shaft taper andthrough a second radial recess in the first part which aligns with thefirst recess. The actuator to activate the actuating device engages theactuating device inside the taper section. This permits overall lengthin the area of the interface to be short, resulting in a high degree ofaccuracy in the concentricity of the cutter of a tool clamped inposition.

In a preferred embodiment of the interface, the caging element isprovided with two lugs to which the chuck jaws are attached. The secondof these lugs has a thread which coacts with a thread provided in thecorresponding chuck jaw. An external thread is provided on the outsideof the second lug which coacts with the internal thread of a cap nut.This cap nut in turn has an external thread on its outer surface whichcoacts with an internal thread in the corresponding chuck jaw. When thecap nut is rotated by means of an actuator, the cap nut on theappropriate lug is moved radially outward in one direction of rotation,as is the chuck jaw positioned on the cap nut. The chuck jaw bearsagainst the inside of the hollow shaft taper so that the opposite jawattached to the caging element also comes into engagement with theinside of the hollow shaft taper. When the cap nut is actuated, thechuck jaws and the caging element move. The passage in the cagingelement is configured such that it aligns with the conduit sections inthe first and second part of the interface in both operating positionsand no changes in direction can negatively affect the coolant/lubricant.

In a particularly preferred embodiment of the interface, a small tubeleads through the first conduit section in the first part, through thepassage in the caging element and through the second conduit section inthe second section of the interface. This ensures that a continuoussmooth inner surface is always provided for the coolant/lubricant overthe entire length of the interface.

Additional embodiments can be derived from the remaining dependentclaims.

The invention is explained in more detail in what follows with referenceto the drawings.

FIG. 1 shows a longitudinal section through an interface in theunclamped state;

FIG. 2 shows a cross-section through the interface shown in FIG. 1;

FIG. 3 shows a longitudinal section through the interface in the clampedstate;

FIG. 4 shows a cross-section through the interface from FIG. 3;

FIG. 5 shows an enlarged side view of a caging element of the interface;

FIG. 6 shows a plan view of the caging element from FIG. 5;

FIG. 7 shows a collet chuck for the interface in a side view and

FIG. 8 shows a plan view of the collet chuck from FIG. 7.

FIG. 1 shows an interface 1 in longitudinal section with a first part 3,from which parts have been cut away for greater clarity, and a secondpart 5. The first part 3 acts as a seat for the second part and istherefore provided with a female taper 7 into which a preferablyhollow-formed taper in the second part 5, a hollow shaft taper 9, isinserted. A first flat surface 11 configured as an annular surface whichcoacts with a second flat surface 13 on the second part 5 is provided onthe face of the first part 3. The second flat surface is located on theend of the hollow shaft taper 9 opposite the free end 15 of said taper.

The second flat surface 13 is created by the main body 14 of the secondpart 5, from which parts have been deleted for reasons of greaterclarity in the view selected here, having a larger outside diameter inthe area of the second flat surface 13 than the hollow shaft taper 9.

The two flat surfaces 11 and 13 each lie in a plane runningperpendicular to the center axis 17 of the interface 1. In the viewshown here, which shows the interface 1 in the unclamped state, the twoflat surfaces 11 and 13 lie at a distance from each other.

A bore 19—in this case cylindrical—is introduced into the hollow shafttaper 9 which serves to locate a clamping fixture configured as a colletchuck 21. An annular groove 23 with a clamping shoulder 25 running at anangle of preferably 30° to the center axis 17 is introduced into thewall of the cylindrical bore 19.

The collet chuck 21 has a continuous central full-length openingpreferably configured as a drill hole 27 which continues in the view inaccordance with FIG. 1 to the left in a first conduit section in thefirst part 3 not shown here, and to the right in a second conduitsection 29 which is introduced into the second part 5. The latterconduit section can, for example, be implemented as a drill hole in themain body 14 of the second part 5. The center axes of the two conduitsections and the drill hole 27 coincide with the center axis 17 of theinterface 1. A small tube 31 is preferably inserted into the firstconduit section, into the drill hole 27 and the second conduit section29 which has a continuous, constant inside diameter and thus functionsas part of a coolant/lubricant supply.

Two projections 33 are provided on the outer wall of the collet chuck 21which are part of a bayonet lock. The collet chuck 21 is firmly anchoredin the first part 3 by this lock. Its locked position is secured bymeans of a heavy-duty dowel pin 35.

Two recesses 39, 39′ are introduced into the main body 37 of the colletchuck 21 which serve to locate chuck jaws 41, 41′. Since the interface 1in FIG. 1 is shown in the unclamped state, the chuck jaws 41. 41′ are intheir radially inward position, at their minimum distance from thecenter axis 17. The chuck jaws 41, 41′ coact with an actuator 43 whichcan urge them radially inward and outward. FIG. 1 shows that the chuckjaws 41, 41′ are provided on their radially outer side with a clampingsurface 45, 45′ which coact with the clamping shoulder 25.

The actuator 43 comprises a caging element 47 on which a first lug 49 isprovided above the center axis 17 and a second lug 51 below the centeraxis. The first chuck jaw 41 is mounted to the upper first lug 49 andthe second chuck jaw 41′ to the lower second lug, where the first chuckjaw 41 is connected by means of a locking pin 53—here running parallelto the center axis 17—to the first lug 49 and the second chuck jaw 41′is connected by means of a thread to the second lug 51. In the case ofthe embodiment shown here, a cap nut 55 is provided between the secondlug 51 and the second chuck jaw 41′.

The actuating device 43 is accessible from the outside. To achieve this,a first recess 57 is preferably introduced into the hollow shaft taper 9and a second recess 59 into the wall of the first part 3, aligning withthe first recess. An annular cover ring 61 which can be moved in theaxial direction, that is, in the direction of the center axis 17 extendsover the second recess 59 and protects the second recess 59 against theentry of dirt. In the embodiment shown here, a rubber element 63 isprovided on the side of the cover ring 61 against the interface 1 whichensures the position of the cover ring 61 and improves its sealingproperties in the area of the second recess 59. It is additionallypossible to furnish the cover ring 61 with a radial recess and to rotatethe ring such that this recess, when the situation requires, aligns withthe first and second recess 57 and 59 to allow access to the actuatingdevice.

An ejector pin 65, running essentially parallel to the center axis 17,is inserted into the main body of the collet chuck 21. The pin is movedaxially to the right by an inclined surface 67 on the second chuck jaw41′ when the interface 1 is in the unclamped state and is pressedagainst a floor 69 of the cylindrical bore 19 and thus pushes the firstand second part 3 and 5 of the first interface apart and allows thesecond part 5 to be removed easily from the first part 3.

FIG. 2 shows the interface from FIG. 1 in cross section. Identical partsare given the same reference numbers so that in this respect referenceis made to the description for FIG. 1.

The drawing shows that the two parts 3 and 5 lie concentrically oneinside the other. It can also be seen that the chuck jaws 41, 41′ are intheir retracted position. The cap nut 55 is threaded fully onto thesecond lug 51, so it is located at a minimum distance from the centeraxis 17. The small tube 31 lies concentric to the center axis.

FIG. 2 also shows the actuating device 43 with the caging element 47 andthe lugs 49 and 51 attached to it. The caging element 47 is providedwith an opening 71 running perpendicular to the plane of theillustration which is configured as an elongated hole. The opening isdimensioned such that the small tube 31 can be passed through it in bothoperating positions, of which the first, the unlocked position, is shownhere.

The chucking element 21 is provided with a recess 73 whose center axiscoincides with a perpendicular diameter line and which is selected to belarge enough that it can receive the caging element 47. The side wallsof the recess 73 guide the caging element 47 in its motion which bringsabout the clamping/unclamping of the two parts 3 and 5.

FIG. 2 shows also that the cap nut 55 is furnished with an actuatingopening 75, for example, with a hexagonal recess which an actuatingelement configured as an Allen key can engage. The shape of the recess,however, is irrelevant for the operation of the actuating device.

FIG. 3 shows an interface 1 in the clamped position. All the elements ofthe collet chuck 21 correspond to those which were explained anddescribed in FIGS. 1 and 2. Consequently there will be no furtherdiscussion of these elements.

The actuating device 43 is activated to clamp the two parts 3 and 5 ofthe interface 1. By means of an actuating element, for example, an Allenkey, the actuation opening 75 of the cap nut 55 is engaged through thefirst and second recesses 57 and 59 and the cap nut is set in rotation.With a rotation in a first direction, the cap nut 55 is shifted from theposition shown in FIGS. 1 and 2 in which it is located at a minimumdistance from the center axis 17: the cap nut 55 is moved outward on thesecond lug 51. This lug is provided with an external thread which mesheswith an internal thread in the cap nut. The cap nut 55, for its part, isfurnished with an external thread on its exterior which meshes with aninternal thread in the second chuck jaw 41′. With a rotation of the capnut 55, for example counter-clockwise, the cap nut is moved outward withrespect to the center axis of the interface 1. The chuck jaw 41′ is alsomoved outward so that pressure is exerted in the radial direction on thecaging element 47. As a result, the first chuck jaw 41 is also movedradially outward. The two chuck jaws move in opposite directions withrespect to the center axis 17 and travel into the circumferential groove23. As a result, the clamping surfaces 45, 45′ of the chuck jaws 41, 41′coact with the clamping shoulder 25. The faces of the clamping surfacesand of the clamping shoulder are aligned such that the second part 5 isurged to the left toward the center axis 17 into the female taper 7until the flat surfaces 11 and 13 are firmly in contact with each other.Together with the clamping shoulder 25, the chuck jaws 41, 41′constitute a wedge ring which acts to advance the hollow shaft taper 9to the left in the direction of the center axis 17 when the chuck jawsare pushed radially outward.

As a result of the radial outward movement of the chuck jaws 41, 41′,the hollow shaft taper 9 is expanded so that its outer surface abutsfirmly against the inner surface of the female taper 7, which results ina very precise clamping of the parts 3 and 5 of the interface 1 and ingreat rigidity. Because the actuating device 43 is acted upon in thearea of the hollow shaft taper 9, in FIGS. 1 and 3 to the left of thefirst flat surface 11, the resulting overall length is extremely shortand consequently the interface is precise and stable.

FIG. 4 shows the interface 1 in the clamped position. It is clearlyrecognizable that the chuck jaws 41, 41′ have been displaced radiallyoutward. The caging element 47 is also displaced. From FIG. 4,particularly by comparison with FIG. 2, it is clear that the cagingelement 47 is moved upward when the interface is clamped. Because thepassage 71 is configured as an elongated hole, the small tube 31 canremain positioned coaxial to the center axis 17 of the interface 1 evenwhen the caging element 47 is shifted to its second operating position.

Overall, it is clear that the small tube 31 can be taken through thepassage 71 with the interface in both the unclamped and the clampedposition. Consequently, a straight coolant/lubricant supply without anychanges of direction is possible so that separation and pooling can bepositively prevented. This is particularly the case if the small tube 31has a constant diameter and a smooth inner wall over its entire length.

FIG. 5 shows—somewhat enlarged—the caging element 47 in a side view. Inthis drawing it is clear that the first lug which runs perpendicular tothe center axis 17 of the interface 1 projects on one side of the mainbody 77 of the caging element 47. Two parallel dot-dash lines can beseen in FIG. 5 which show the path of the center axis 17 of theinterface 1 in the different operating positions of the actuatingelement 43. When the interface 1 is not clamped, the center axis 17 ofthe interface 1 runs higher up than in the clamped position. Acomparison of FIGS. 2 and 4 shows this particularly clearly: in theunclamped state of the interface 1, the center axis 17, and with it thesmall tube 31, runs inside the passage 71 at the top. When the cagingelement 47 is moved upward to clamp the interface 1, the center axis 17runs lower down through the passage 71. The small tube 31 is alsopositioned lower down, which can be seen from FIG. 4.

The first lug is provided with a recess 79 which locates the locking pin53 which is shown in FIGS. 1 and 3.

The second lug 51 is located diametrically opposite the first lug 49.Here it can be seen clearly that it has an external thread which mesheswith an internal thread on the cap nut 55, which is not shown here. Ifthe cap nut is rotated in a first direction, it moves in the directionof the center axis 83 of the two lugs 49 and 51 toward the center axis17. With an opposite direction of rotation, it moves outward and awayfrom the main body 77 of the caging element 47. This position is shownin FIG. 4, while the radially inward position of the cap nut 55 isreproduced in FIG. 2.

In the drawing from FIG. 6, the caging element 47 is rotated by 90° sothat it is possible to see into the passage 71 in the main body 77 ofthe caging element 47. The outer contour of the small tube 31 isindicated by a circle 83. It is clear that the dimensions of the passage71 are chosen such that the small tube 31 can be taken through thepassage 71 in both operating positions of the actuating device 43. Evenwithout a small tube of this kind, a continuous straightcoolant/lubricant passage can be realized in both instances.

FIG. 6 also shows the oppositely located lugs 49 and 51. Here the recess79 through which the locking pin 53 can be passed is shown in plan view.

FIG. 7 shows the collet chuck 21 without any installed parts. Identicalparts are given the same reference numbers so that reference is made inthis regard to the description for the preceding figures.

The projections 33 at the left end of the collet chuck 21 can beidentified. They form part of the bayonet lock by means of which thecollet chuck is anchored in the first part 3 of the interface 1.Recesses 39, 39′ in which the chuck jaws 41, 41′ come to rest can alsobe identified. FIG. 7 also shows the recess 73 which traverses the mainbody 37 of the collet chuck from top to bottom and serves to locate thecaging element 47.

The right front part of the collect chuck 21 is shown in partial sectionto show a hole 85 in which the ejector pin 65 is housed. The length ofthe ejector pin is selected such that, on the one hand, it extendssomewhat into the recess 39′ to be able to coact there with chuck jaw41′. On the other hand, the ejector pin 65 projects to the right beyondthe face 87 of the collect chuck 21 in order to be able to exertpressure on the floor 69 of the cylindrical hole 19 in the second part 5which serves to separate the two parts 3 and 5 when the interface 1 isin the unclamped state.

Finally, FIG. 8 shows the collect chuck 21 depicted in FIG. 7 in planview. Identical parts are given the same reference numbers. Here, therectangular contour of the recess 39 can be seen and the recess 73 whichtraverses the floor of the recess and which serves to locate the cagingelement 47.

In what follows, the operation of the interface will be discussed onceagain in detail:

The interface 1 can be any type of connecting point between a machinetool equipped with a machine spindle and a tool, which includesconnecting points between intermediate elements, extensions and adapterswhich connect to each other, to the machine spindle and/or to a tool.Preferably the interface 1 shown here is a machine spindle whichrepresents the first part 3 and a tool which represents the second part5.

The connection between machine spindle and tool is brought about in theinitial unclamped state by the tool, meaning the second part 5, beinginserted into the machine spindle, meaning the first part 3, wherein thehollow shaft taper 9 engages the female taper 7. The flat surface 11 ofthe first part 3 is at a small distance from the second flat surface 13of the second part 5. The chuck jaws 41, 41′ lie at a minimum distancefrom the axis of rotation 17 in the radially inward retracted position.This is achieved by inserting an actuating device, for example, an Allenkey, through the recesses 59 and 57 into the actuating opening 75 of thecap nut 55 and rotating said nut such that it is located in its maximuminward position, meaning at a minimum distance from the center axis 17.Not only the cap nut 55 is moved in the direction of the center axis 17as the result of its rotation. The chuck jaw 41′ coacting with the capnut 55 is moved toward the center axis 17. Since the chuck jaw 41′finally comes to rest against the main body 37 of the collet chuck 21,the opposite chuck jaw 41 is similarly drawn inward. The chuck jaws 41,41′ are preferably configured such that their outer surface aligns withthe circumferential surface of the collect chuck 21 when it is movedcompletely inward in the radial direction.

The position discussed here is shown in FIGS. 1 and 2 in which theinterface 1 can be seen in the unclamped state and the actuating element43 is in its initial operating position, that is, in the releasedposition.

To clamp the interface 1, the actuating device 43 is activated. That isto say, the cap nut 55 is rotated such that it moves outward onto thesecond lug 51 and in so doing drives the corresponding chuck jaw 41′ andmoves it outward in similar fashion. The displacement of the chuck jaw41′ for its part is based firstly on the outward movement of the capnut, but secondly in this case, also on the fact that the cap nut 55 hasan external thread which coacts with the internal thread in the chuckjaw 41′ so that a relative motion takes place between cap nut 55 andchuck jaw 41′. The internal and external threads on the cap nut 55 havethe same pitch in order to effect equal movement of the chuck jaws 41,41′.

When the cap nut 55 is rotated, it is not only the chuck jaws 41, 41′that are shifted inward or outward diametrically opposite one another,the cage element 47 is moved up or down: in order to reach the unclampedposition for the interface 1, the cage element 47 is moved down, and toreach the clamped operating position it is moved up.

When the two pieces 3 and 5 are clamped together, the chuck jaws 41, 41′are moved outward. Through the interaction of the clamping surfaces 45,45′ and the clamping shoulder described above, the hollow shaft taper 9is pulled to the left into the interior of the female taper 7 becausethe collet chuck 21 is securely anchored in the first part 3 by means ofthe bayonet lock and cannot be shifted in the axial direction. Thehollow shaft taper is expanded and pressed against the inner wall of thefemale taper 7. At the same time, the flat surfaces 11 and 13 arepressed firmly against each other so that optimal alignment of theinterface 1 is achieved along with an extremely high degree of rigidity.Since the chuck jaw 41′ is moved radially outward, the ejector pin 45can be shifted to the left into the interior of the recess 39′. With anopposite movement of the chuck jaw 41′, an inclined surface facing thecenter axis 17 at an angle acts on the ejector pin 75 such that thelatter is pushed to the right and strikes the floor 69 of thecylindrical hole 19. With an additional movement of the chuck jaw 41′ tothe inside, the ejector pin 75 is urged to the right with such forcethat the two parts 3 and 5 are pushed apart and can be easily separated.

The forces that can be generated with the actuating device 43 are sohigh that secure clamping of the parts 3 and 5 is possible even whenchanging the tool manually. Similarly, such great force can be appliedwhen the actuating device 43 is activated manually that the two parts 3and 5 can be separated by means of the ejector pin 65.

It is possible to implement a central coolant supply by means of thecaging element 47 of the actuating device 43. For this, a first conduitsection in the first part 3 aligns with the passage 71 in the cagingelement 47 and with a second conduit section 29 in the second part 5.Since the passage 71 is configured as an elongated hole, a centralpassage for the coolant/lubricant can be implemented in both operatingpositions that are shown in FIGS. 2 and 4. Preferably a small tube 31 isinserted here to avoid all steps and edges in the area of thecoolant/lubricant supply which would promote separation and pooling ofthe air/oil mixture when minimum quantity lubrication is used.

Because activation of the actuating device 43 in the embodiment shownhere is implemented in the area of the hollow shaft taper 9, that is, tothe left of the first flat surface 11, while ensuring optimallubrication even when using minimum quantity lubrication, a very shortoverall length can be achieved, which results in extremely high rigidityin the interface 1 and exact concentricity because of the shortoverhang.

Moreover, it can be seen that the interface 1 is extremely simple inconstruction because the collet chuck 21 and its actuating device 43require very few parts.

In order to protect the interface 1 from contamination, the cover ring61 is provided which covers the access point for the actuating device 43during operation and uncovers it as required. It is conceivable to movethe cover ring 61 in the axial direction of the interface 1 to provideaccess or to equip it with a recess running radially which can uncoverthe access openings to the actuating device by rotating the ring, whilethe actuating device remains covered during operation.

From the explanations, it is clear that the actuating device 43 can alsobe designed differently while retaining the basic principle describedhere. For example, it is possible to anchor the second lug 51 to berotatable in the main body 77 of the caging element 47. If the lug hasan external thread which meshes with an internal thread in the secondchuck jaw 41′, the latter is moved in a radial direction inward oroutward when the second lug 51 is rotated. This causes the interface tobe clamped or unclamped. However, the embodiment described here with thecap nut 55 is preferred, because a greater axial movement of the chuckjaw 41′ can be achieved through a rotational movement of the cap nut 55.

Similarly it would be conceivable to anchor a sleeve with an internalthread rotatably in the second chuck jaw 41′ which cannot be movedradially to the center axis inside the chuck jaw 41′ and which coactswith an external thread on the second lug 51. However, this would alsoresult in a smaller axial displacement of the chuck jaw with a specificangle of rotation than with the embodiment shown here with the cap nut55.

It is crucial that the actuating device 43 is implemented in such a way,meaning that it has a caging element 47, that a centralcoolant/lubricant conduit is not obstructed through a displacementperpendicular to the axis of rotation 17. This can be achieved by asuitable passage 71 in the caging element 47, as described above.Transitions, edges and similar between the first part 3 and the colletchuck 21 and between the latter and the second part 5 can be avoided bythe use of a small tube 31, which was explained above in detail.Moreover, this small tube also eliminates edges and transitions in thearea of the passage 71 for the caging element 47. It also allows atrouble-free coolant/lubricant supply in the area of the interface 1.

In addition, a very short overall shape is achieved, which is madepossible by the flat surface 11 being located very close to the bearingpoints of a machine spindle, not shown here, which could correspond tothe first part 3.

1. Interface of a tool having a first part comprising a seat configuredas a female taper, which part has a first conduit section locatedconcentrically with its center axis, a second part having a hollow shafttaper introduceable into the female taper, which part has a secondconduit section located concentrically with its center axis and a holewith a wall which is provided with an annular groove surrounding aclamping shoulder, where the center axes of the first and second partsalign, and having a collet chuck anchored in the first part having twochuck jaws which comprises an actuating device coacting with the chuckjaws which can be activated by means of an actuating element, where thechuck jaws engage the annular groove from inside in one operatingposition, wherein the collet chuck has a full-length central passagewhich continues firstly into the first conduit section in the first partand secondly into the second conduit section in the second part and inthat the actuating device has a caging element which can be shifted totwo operating positions and which has a central passage which is locatedsuch that the center axes of the first and second parts run through saidpassage in both operating positions, wherein the actuating device isaccessible through a first radial recess in the hollow shaft taper andthrough a second radial recess provided in the first part and aligningwith the first recess.
 2. Interface in accordance with claim 1, whereintwo lugs are provided on the caging element.
 3. Interface in accordancewith claim 2, wherein the first lug is connected to a first chuck jaw.4. Interface in accordance with claim 3, wherein the second lug has anexternal thread which coacts with a second chuck jaw.
 5. Interface inaccordance with claim 1, wherein a cap nut is provided which isfurnished with an internal thread coacting with the second lug and anexternal thread coacting with the second chuck jaw.
 6. Interface inaccordance with claim 5, wherein the cap nut is provided with anactuating opening for an actuator on the side facing away from thesecond lug, preferably configured as an indentation.
 7. Interface inaccordance with claim 5, wherein the internal thread and the externalthread on the cap nut have the same pitch.
 8. Interface in accordancewith claim 1, further comprising a small tube which projects at leastthrough areas of the conduit section in the first part, of the passagein the caging element and at least partially through areas of the secondconduit section in the second part.